The invention relates to solid compositions containing antimicrobial agents. The invention more specifically relates to non-flowing solids containing particular antimicrobial agents where the solids can be used in dispensers which direct water at the surface of the solid to dissolve a selected amount of the solid to produce a sanitizing, deodorizing or disinfecting solution.
An extensive number of antimicrobial compositions are commercially available in liquid or power form. The liquid compositions typically have active ingredients in the range of 5 percent to 15 percent by weight of the product, but highly concentrated liquid products can contain up to 80% active ingredients. Concentrated liquid products must be diluted before use. Ready to use liquid products can have concentrations of active ingredients at least as low as 0.02 percent by weight of the product. All of these liquid products contain significant amounts of water, alcohols and/or other materials as diluents. Because these products are diluted, they utilize more packaging materials and result in higher shipping weights to transport a given amount of active material than is required for a highly concentrated solid.
A significant disadvantage of powder or granular products for commercial applications is that they are not as accurately controllable in dispensing equipment as liquids. Powder systems can require manually scooping a quantity of powder for each use, thus not taking advantage of the ease, accuracy and hands-off labor savings of liquid dispensers. Also, powders can cake if exposed to high humidity or temperatures. Once they become caked, they cannot be easily removed from their shipping container. Non-homogeneous powders can segregate in their shipping containers, in other words, separate or stratify by particle size or density, resulting in non-uniform mixture that may not be appropriate for ultimate use applications.
Some disinfectants and sanitizers are considered corrosive which creates hazards in shipping and handling. Spilled liquid material from leaking containers or mishandling the product can come into contact with skin or eyes causing tissue damage, pain and discomfort. Powders can create a safety hazard because particles of irritating or corrosive materials can exit their container or become airborne allowing the particles to come into direct contact with tissue, such as skin or lungs, causing burns or discomfort. A solid antimicrobial product would not be easily capable of creating this hazard since it cannot leak out of its container nor can it be spilled in handling.
Because of stringent regulatory controls over disinfectants and sanitizers especially for institutional uses, solutions for application typically must be prepared with specific and exacting dilution ratios. Typical sanitizers and disinfectants concentrates are mixed with water to obtain a solution with a specific concentration for applications. These solutions are used to sanitize or disinfect objects and surfaces such as counter tops, tables, floors, walls, dishes, utensils and fabrics. Many institutions require these products including food processing operations, nursing homes, health care facilities, kitchens, and laundries. Here, the terms disinfectant and sanitizer are used interchangeably to denote an antimicrobial agent even though the terms may have precise and distinct meanings in institutional use and under regulatory control These products are also effective at deodorizing because they can destroy odor causing bacteria and other microbes.
While liquid and powder products can be measured by hand and accurately diluted, this process is slow and potentially hazardous if the materials are corrosive. Liquid products can be properly diluted using dispensing apparatuses to product solutions for application, but this does not eliminate all of the inconveniences and hazards of the handling of liquid. Recently, dispensers have been developed for the accurate and convenient dispensing of solids. For example, U.S. Pat. No. 5,342,587 to Laughlin et al. describes a solid dispensing device where the solid is provided in a plastic bottle that is inverted over a bowl. Water is sprayed on the solid to produce a solution that is drained from the bowl.
Some sanitizer or disinfectant concentrates have cleaning agents added to the antimicrobial compounds to create cleaner/disinfectants. Commercially available liquid and powder cleaner/disinfectants clean soils from surfaces as well as kill microorganisms. The cleaning agents in these products are typically alkaline and include anionic or nonionic surfactants along with other additives such as alkaline builders and metal ion sequestering agents. Liquid and powder cleaner/disinfectants have the same disadvantage as liquid and powder forms of other sanitizing products.
Solid sanitizing compositions avoid the deficiencies of either liquids or powders. The solids provide for convenient and safe handling and can be dispensed accurately and conveniently using solid dispensers. The preferred solid sanitizing products are in a plastic container, such as a bottle or jar, with a label indicating that the contents have antimicrobial properties. The container will contain a non-flowable solid including greater than about 0.02 percent by weight antimicrobial compounds. The solid will preferably contain greater that about 0.5 percent by weight antimicrobial compounds, more preferably greater than 2 percent by weight antimicrobial compounds and even more preferably greater than 5 percent by weight antimicrobial compounds.
The antimicrobial compounds are preferably selected from the group consisting of quaternary ammonium salts, fatty amines and diamines, chlorhexidine gluconate, phenol, derivative of phenol, parachloro metaxylenol and mixtures thereof. The quaternary ammonium salts will preferably have at least one alkyl substituent on the quaternary nitrogen with C6 to C18 hydrocarbon units.
The preferred amines and diamines have at least one alkyl substituent with carbon chain lengths in the range of C10-C18.
The preferred solid sanitizing compositions consist essentially of greater than about 0.02 percent weight of an antimicrobial compound and between 0 and 99.98 percent of a cleaning composition. The cleaning composition can be alkaline or neutral pH. The cleaning compositions preferably comprise compounds selected from the group consisting of surfactants, alkaline builders and polyvalent metal sequestering agents.
The invention also includes methods of using and methods of making solid sanitizing compositions. One preferred method of using a solid sanitizing composition of the invention involves producing an antimicrobial use solution using a dispenser comprising a bowl with a drain, a tube connected to the drain and a spray nozzle for directing water up from the bowl. An open bottle containing a solid sanitizing composition is inverted into the bowl such that water from the spray nozzle is directed into the open bottle. The spray of water dissolves a portion of the sanitizing composition to form an aqueous solution of antimicrobial compounds. The resulting antimicrobial solutions can be used particularly in a variety of industrial and institutional applications including laundry and hard surface cleaning. The solid antimicrobial composition preferably comprises greater than about 0.02 percent by weight of antimicrobial compound selected from the group consisting of quaternary ammonium salts, fatty amines and diamines, chlorhexidine gluconate, phenol, derivatives of phenol, parachloro metaxylenol and mixtures thereof.
Another preferred method of using a solid sanitizing composition of the invention involves producing an antimicrobial use solution using a dispenser having a bowl with a drain at the bottom of the bowl, a spray nozzle for directing water upward from the bowl, a tube connected to the opening of the drain and an aqueous solution supply connecting with the tube from the drain to form a combined flow. A bottle containing a solid antimicrobial composition is inverted into the bowl of the dispenser. The spray nozzle is directed upward into the open bottle of the solid antimicrobial composition. The relative flow volumes into the spray nozzle and the aqueous solution supply are adjusted to produce a desired concentration of antimicrobial, deodorizing solution in the combined flow.
There are several methods of producing the solid sanitizing compositions. The first method involves forming a melted composition consisting essentially of antimicrobial compounds and between 0 and 99.98 percent by weight of an alkaline cleaning composition. The solid sanitizing composition preferably comprises greater than 0.02 percent by weight antimicrobial compounds and more preferably greater than about 1 percent by weight antimicrobial compounds. The melted composition is poured into a container where it solidifies upon cooling.
A second method of producing solid sanitizing compositions involves heating a solution of antimicrobial compounds to remove sufficient solvent to form a solvent depleted composition. The solvent depleted composition is poured into a container. The solvent depleted composition cools to form a non-flowable composition. A solvent depleted composition is a composition that will cool to form a non-flowable material upon cooling.
A third method of producing solid sanitizing compositions begins by melting a solid carrier. A powder antimicrobial composition is mixed into the melted carrier to form a melted antimicrobial composition. The melted antimicrobial composition is poured into a container. Upon cooling to room temperature, the composition forms a solid antimicrobial composition.
The fourth method of producing a solid sanitizing composition involves mixing an aqueous solution of an antimicrobial compound with an anhydrous hydratable salt to form a homogeneous dispersion. The aqueous solution of the antimicrobial compound can be preformed or it can be formed in situ by adding a powder antimicrobial compound and water or another aqueous solution. The compounds in the homogenous solution may or may not be dissolved. The homogeneous dispersion is poured into a container. The container is stored until a solid composition is formed in the container.